Easiest to sharpen?

The old tan bear razorheads are easy to sharpen using a variety of techniques.  I have killed deer with them using all of the methods file sharpened, diamond honed, carbide scraped and barbershop straps. The file edge as used by Bear himself is easy and quick.

[Earthdog]

Once you have a good sharpening method,most heads are pretty easy to sharpen.
I use two files,a hoof rasp/file and a mill file.
Finish with a steel an it's all good.

[Jim Stewart]

Easiest for me?  Ribteks; Grobet (file) and finish on a leather strop...